The present invention relates to a water-permeable ceramic material, and more particularly, to a water-permeable ceramic material having good water draining, sound absorbing and anti-slip properties and which hence is particularly suitable for use as a floor structure.
Floors in buildings and outdoor facilities are conventionally made of concrete, asphalt, tiles, stoneware, bricks, interlocking blocks, plastic sheets and a variety of resins. These flooring materials have the following defects.
(1) They are inherently impermeable to water and are unable to absorb or drain water, and, therefore, spilled water or oils or falling rain-drops either stand or flow on the surface;
(2) They become slippery when made wet by water or oils;
(3) Because of their low sound absorbing ability, noise is caused by footsteps or vehicles passing thereover.
The modern world around us contains many places that are constantly exposed to the chance of water or oils spilling or running over them, and among these hazardous places are underground passages, the premises of railway stations, pool sides, public toilets, baths, the tops of buildings, parks, inclined sidewalks and factories. Because of the flooring materials used in these places, they often become slippery when made wet by water, oils or rain, and the number of accidents in which people slip and get hurt is increasingly catching the newspaper headlines. In Japan, the practice of covering roads or streets with concrete or asphalt continues to spread. However, this means that raindrops falling on paved surfaces flow over these surfaces and do not reach the ground itself. Being thus unable to absorb sufficient water to live on, trees along sidewalks or at parks are often withered to death in summer when precipitations are low.
U.S. Pat. No. 4,481,124 relates to thermal shock resistant, porous sound-absorbing ceramic bodies used in walls and in exhaust mufflers. The structure of these prior sound-absorbing ceramic bodies is made up of highly porous ceramic particles surrounded by an inorganic binder to form a matrix. The bulk density of the ceramic particles used in the bodies described in U.S. Pat. No. 4,481,124 is recited as being from 1.2 to 2.0 kg/l. Assuming an average true density of 2.4 kg/l for the individual particles, and applying the standard formula for determining porosity of ##EQU1## where D.sub.T is the true density and D.sub.B is the bulk density, the porosity of these individual ceramic particles ranges from about 16.7 to 50%.